Everybody knows that if you

have a hearing loss, you don't hear many of the sounds

around you. Other sounds may be heard, but they're not

quite loud enough.

Another common problem for

people with hearing loss is that many sounds are simply

too loud. How can someone who has a hearing loss find

many sounds loud enough to be uncomfortable - even

painful??

This hypersensitivity to

loud sounds is called recruitment and is not unusual for

someone with a sensorineural (inner ear) hearing loss.

The explanation lies in how the ear works.

Sensorineural loss is the

most common type of hearing loss. In cases of

sensorineural hearing loss, some of the hair cells of the

inner ear have been damaged and are not responding to

softer sounds. However, other hair cells, the ones that

respond to louder sounds, may be just as sensitive as

ever.

Thus, a person with

sensorineural hearing loss (and recruitment) might not

hear soft sounds at all; Might hear moderate sounds

(although not quite loud enough); and loud sounds might

suddenly be too loud because the inner ear hair cells

have suddenly been activated.

The Comfortable Listening

Range:

As a result of this

hypersensitivity, most people with hearing loss have a

limited range of comfortable hearing. Many sounds are too

soft to be heard, while others are simply too loud to be

tolerated.

To put it in numbers,

someone with normal hearing might have a comfortable

listening range of 100 decibels (the range between what

is barely heard to the limit of what can be tolerated).

The typical comfortable listening range of someone with a

moderate loss might be only 45 decibels- a much more

limited range.

Hypersensitivity and

Hearing Aids:

There are important

implications for hearing aid use. Hearing aids must

amplify sounds enough to be heard, but not amplify sounds

beyond the user's tolerance level. Older hearing aids

were limited in their ability to do this. If the hearing

aid amplified soft sounds enough to be heard, loud sounds

would be too loud; if loud sounds were kept in the

comfortable range, soft sounds would be too soft. Usually

the hearing aid user would use a manual volume wheel to

try to keep sounds in the comfortable range.

The new generation of high

technology hearing aids, with microchips, programmability

and digital processing are much more successful at

handling the problem of recruitment. Modern hearing aids

monitor the incoming sound and adjust automatically. Soft

sounds may still be soft and loud sounds may still be

loud (as they are for everyone), but today's hearing aids

are much more effective at keeping sounds within any

individual's comfortable listening range.